where \(\gamma \in [0, r]\)  is fixed.
Unlike the classical Sturm–Liouville operator, operators with frozen argument are non-local. For this reason, the methods of the classical inverse problems theory [1]}, [2]}, [3]} are inapplicable for them. Meanwhile, non-local operators have applications in many areas of mathematics and natural science, see [4]}, [5]}, [6]}.
